/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/Sampling/MeshSurfaceSampler.h
The Initialize function must have been called withEMeshSurfaceSamplerQueryType::UVOnlyIf the query location is not on a triangle in the Mesh then return false (SampleInfo will be invalid)
virtual bool QuerySampleInfo ( const FVector2d & UV, [FMeshUVSampleInfo](API\Plugins\DynamicMesh\Sampling\FMeshUVSampleInfo) & SampleInfo )